The macro BOOST_GEOMETRY_REGISTER_MULTI_LINESTRING_TEMPLATED registers
a templated multi_linestring such that it is recognized by Boost.Geometry
and that Boost.Geometry functionality can used with the specified type.
The type must have one template parameter, which should be a linestring
type, and should not be specified. Boost.Geometry takes care of inserting
the template parameter. Hence all types of this templated multi_linestring
are registered, regardless of their point type.